1. Heat grill and get wok/pan hot 2. Add sliced onions to the Wok/ pan Let onions cook until soft. Then add salt and pepper to taste and continue cooking. Add balsamic vinegar to onions and stir until mixed. 3. Add Ground chuck, Kosher salt and steak seasoning to a bowl and combine ingredients. 4. Form patties and place on hot grill until center of burgers are almost firm. Approx. 5 minutes 5. Top burgers with feta and continue cooking until feta is softened. 6. Spread Mayo on bottom bun and top with Romaine lettuce. 7. Place burger on bun with lettuce 8. Top burger with 1/6th of the onion mixture and place top of bun on entire burger.